Materials Literature
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Urease was purified 24-fold from extracts of Klebsiella aerogenes. The enzyme has a molecular weight of 230,000 as determined by gel filtration, is highly substrate specific, and has a Km for urea of 0.7 mM. A mutant strain lacking urease was isolated; it failed to grow with urea as the sole source of nitrogen but did…
The partitioning of NaAlSi/sub 3/O/sub 8/ between coexisting microcline and plagioclase solid-solutions is modeled using published Margules parameters for microcline-low albite solid-solutions. Variations in the structural state of the alkali feldspar may shift the temperature calculated from coexisting feldspar pairs…
lnfrared spectra ofthe coordinated water in palygorskite were studied at different degrees of exchange of deuterons and protons. The single peaks observed for the bending fundamental of isotopically diluted HrO and DzO show that all the coordinated water molecules are equivalent, as suggested by Bradley's structure de…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSystematic synthesis design. 6. Yield analysis and convergencyJames B. HendricksonCite this: J. Am. Chem. Soc. 1977, 99, 16, 5439–5450Publication Date (Print):August 1, 1977Publication History Published online1 May 2002Published inissue 1 August 1977https://doi.org/10.1021/j…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectronic structure of low-spin cobalt(II) Schiff base complexesM. A. HitchmanCite this: Inorg. Chem. 1977, 16, 8, 1985–1993Publication Date (Print):August 1, 1977Publication History Published online1 May 2002Published inissue 1 August 1977https://pubs.acs.org/doi/10.1021/i…
A new experimental approach is presented for studying the charge-transfer process involved in the chemisorption on polar semiconductors. This approach utilizes the surface piezoelectric effect, contact potential difference measurements, and surface photovoltage spectroscopy. From the study of oxygen adsorption on ZnO…
The single-crystal material has a resistivity at 300 degrees C of 4.7 Omega cm and an activation energy of 0.13 eV. In the polycrystalline case it has been possible to separate out the bulk and grain boundary contributions to the total electrolyte resistance. These have activation energies of 0.15 and 0.26 eV respecti…
Hot corrosion is a form of accelerated oxidation of alloys which can occur in combustion gases in the presence of impurities. The characteristics of the reaction are defined by describing practical examples, and then the results of a variety of laboratory experiments are considered in relation to the practical process…
A technique is presented for the simultaneous determination of thermal conductivity and thermal diffusivity of biomaterials. Measurements are derived from the transient power supplied to a thermistor probe operated in a self-heated mode. The thermal properties are extracted through the use of an appropriate thermal mo…
The whole-pattern least-squares fitting method (herein called the pattern-fitting structure-refinement, PFSR, method) developed by Rietveld and used by many with neutron powder data has been extended for use with X-ray powder diffractometer data. Examples of PFSR for specimens in five different space groups are given.…
Lithium ion conductivity in solid solutions formed between and has been measured as a function of temperature and composition using a‐c techniques. Highest conductivities were found at 50 and 60 mole percent (m/o) phosphate. Empirical conductivity parameters are presented and qualitatively analyzed in terms of structu…
A lattice dislocation may lower its elastic energy by dissociation in a high angle grain boundary. The absorption process involves the separation of the product grain boundary dislocations at a rate limited in general by climb and their interaction with any pre-existing network. This description of the absorption proc…
Pd and Pt clusters on carbon substrates have been studied by x-ray photoemission spectroscopy (XPS). Variations in valence- and core-level spectra with cluster size have been observed. Single-atom centers appear to exist in the ${d}^{9}{s}^{1}$ configuration. The $d$-electron count increases with cluster size, and in…
A completely general theory is presented which can be used to describe both anion and cation adsorption on amphoteric oxide surfaces. It takes account of the fact that both the surfaces and adsorbing species are charged and that the surfaces change their charge when ionic adsorption takes place. The theory is applicab…
Deuterium permeation, diffusion, and solubility measurements have been made for several types of vitreous silica at temperatures ranging from 0 to 800 °C. The activation energies for permeation and diffusion were found to be somewhat temperature dependent. Isotope exchange between structural hydroxyl and the diffusing…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStudy of .alpha.- and .beta.-enneatungstosilicates and -germanatesGilbert. Herve and Andre. TezeCite this: Inorg. Chem. 1977, 16, 8, 2115–2117Publication Date (Print):August 1, 1977Publication History Published online1 May 2002Published inissue 1 August 1977https://pubs.acs.…
Zinc oxide ceramics containing rare earth metal oxide and cobalt oxide which exhibit non-ohmic current-voltage characteristics were studied. The nonlinearity was similar to that of the zinc oxide varistor containing Bi 2 O 3 and other additives. According to microstructural observations, the intergranular layer of the…
A theory for inelastic scattering of fast electrons in solids is developed, based on an extension of the theory of scattering in an electron gas. Values of the inverse mean free path and related optical potential can be computed quite conveniently. It appears that, particularly in the case of solids characterized by h…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTVesicles of variable diameter prepared by a modified injection methodJ. M. H. Kremer, M. W. Van der Esker, C. Pathmamanoharan, and P. H. WiersemaCite this: Biochemistry 1977, 16, 17, 3932–3935Publication Date (Print):August 23, 1977Publication History Published online1 May 2…
A method for the isolation of an iron-molybdenum cofactor (FeMoCo) from component I of nitrogenase is described. This method is used to isolate FeMoCo from aerobic, anaerobic, facultative, and photosynthetic nitrogen-fixing organisms. The Fe/Mo ratio in the FeMoCo from Azotobacter vinelandii and Clostridium pasteurian…